Submission #1196252

#	Time	Username	Problem	Language	Result	Execution time	Memory
1196252		cpismylifeOwO	Mobile (BOI12_mobile)	C++20	85 / 100	1020 ms	31760 KiB

mobile

#include <bits/stdc++.h>

using namespace std;

const long long mod = 1e9 + 7;
const int MaxN = 1e6 + 5;

int n;
long double l;
pair<long double, long double> arr[MaxN];

void Inp()
{
    cin >> n >> l;
    for (int x = 1; x <= n; x++)
    {
        cin >> arr[x].first >> arr[x].second;
    }
}

pair<long double, long double> now[3];
pair<long double, long double> add[3];
pair<long double, long double> tmp[3];

bool Check(long double k)
{
    int i = 1, j = 1;
    now[i] = make_pair(0, l);
    for (int x = 1; x <= n; x++)
    {
        if (abs(arr[x].second) >= k)
        {
            continue;
        }
        long double p = sqrtl(k * k - arr[x].second * arr[x].second);
        j = 0;
        if (arr[x].first - p >= 0.0)
        {
            j++;
            add[j] = make_pair(0, min((long double)arr[x].first - p, l));
        }
        if (arr[x].first + p <= l)
        {
            j++;
            add[j] = make_pair(max((long double)arr[x].first + p, (long double)0), l);
        }
        int tmpi = i;
        for (int y = 1; y <= i; y++)
        {
            tmp[y] = now[y];
        }
        i = 0;
        for (int x = 1; x <= tmpi; x++)
        {
            for (int y = 1; y <= j; y++)
            {
                long double l = max(tmp[x].first, add[y].first), r = min(tmp[x].second, add[y].second);
                if (l <= r)
                {
                    i++;
                    now[i] = make_pair(l, r);
                }
            }
        }
    }
    return i > 0;
}

void Exc()
{
    long double l = 0, r = 1e10, mid, res = 0;
    while (r - l > 1e-3)
    {
        mid = (l + r) / 2.0;
        if (Check(mid))
        {
            res = mid;
            l = mid;
        }
        else
        {
            r = mid;
        }
    }
    cout << fixed << setprecision(3) << res;
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    int test = 1;
    //cin >> test;
    for (int x = 1; x <= test; x++)
    {
        Inp();
        Exc();
    }
    return 0;
}

• Subtask 1: 4 / 4
• Subtask 2: 4 / 4
• Subtask 3: 4 / 4
• Subtask 4: 4 / 4
• Subtask 5: 4 / 4
• Subtask 6: 5 / 5
• Subtask 7: 5 / 5
• Subtask 8: 5 / 5
• Subtask 9: 5 / 5
• Subtask 10: 5 / 5
• Subtask 11: 5 / 5
• Subtask 12: 5 / 5
• Subtask 13: 0 / 5
• Subtask 14: 5 / 5
• Subtask 15: 5 / 5
• Subtask 16: 5 / 5
• Subtask 17: 0 / 5
• Subtask 18: 5 / 5
• Subtask 19: 5 / 5
• Subtask 20: 0 / 5
• Subtask 21: 5 / 5